Identification—
A:
Shake a quantity of powdered Tablets,equivalent to about 50mg of quinidine sulfate,with 100mLof dilute sulfuric acid (1in 350),and filter:the filtrate so obtained exhibits a vivid blue fluorescence.On the addition of a few drops of hydrochloric acid,the fluorescence disappears.
B:
In the test for
Chromatographic purity,the
RFvalue of the principal spot obtained from the
Test preparationcorresponds to that from the
Standard preparation.
C:
Shake a quantity of the powdered Tablets,equivalent to about 100mg of quinidine sulfate,with 10mLof dilute hydrochloric acid (1in 100),and filter:the filtrate so obtained responds to the tests for Sulfate á191ñ.
Drug release á724ñ—
Test 1—
If the product complies with the test,the labeling indicates that the product meets USPDrug Release Test 1.
Medium:
0.1Nhydrochloric acid;900mL.
Apparatus 1:
100rpm.
Times:
1hour;4hours;12hours.
Procedure—
Using filtered portions of the solution under test,diluted with 0.1Nhydrochloric acid if necessary,determine the amount of quinidine sulfate dissolved from UVabsorbances at the wavelength of maximum absorbance at about 248nm by comparison with a Standard solution having a known concentration of
USP Quinidine Sulfate RSin the same medium.
Tolerances—
The percentages of the labeled amount of quinidine sulfate dissolved at the times specified conform to
Acceptance Table 1.
| Time (hours) |
Amount dissolved |
| 1 |
between 20%and 50% |
| 4 |
between 43%and 73% |
| 12 |
not less than 70% |
Test 2—
If the product complies with this test,the labeling indicates that the product meets USPDrug Release Test 2.
Medium:
0.1Nhydrochloric acid;900mL.
Apparatus 1:
100rpm.
Times:
1hour;4hours;12hours.
Procedure—
Proceed as directed for Test 1.
Tolerances—
The percentages of the labeled amount of (C
20H
24N
2O
2)
2·H
2SO
4·2H
2Odissolved at the times specified conform to
Acceptance Table 1.
| Time (hours) |
Amount dissolved |
| 1 |
between 10%and 35% |
| 4 |
between 30%and 55% |
| 12 |
not less than 75% |
Chromatographic purity—
Shake a quantity of powdered Tablets,equivalent to about 150mg of quinidine sulfate,with 25mLof diluted alcohol for 10minutes,and filter.Using the filtrate as the test solution,proceed as directed in the test for
Chromatographic purityunder
Quinidine Sulfate.